| Background and Objective:There is a lot of evidence that the development of diabetic nephropathy(DN)is associated with renal mircrovascular abnormalities and chronic hypoxia,and attributed mainly to apoptosis of renal inherent cells.Our previous study has confirmed that angiopoietin-1(Ang-1)and inhibiting degradation of hypoxia-inducible factor(HIF)could improve the abnormal expression of angiogenesis-and hypoxia-relecated factors,and relieve the microvascular disease and hypoxia state in diabetic kidney.In this study,Ang-1 and L-mimosine(an inhibitor of HIF degradation)will be assessed for their effects on diabetic nephroprotection in the aspect of cell apoptosis.Methods: Recombinant adenovirus vector expressing Ang-1(Ad-Ang-1)was constructed.SD diabetic rat was built by intraperitoneal injection with streptozotocin(STZ).The experimental rats were divided into six groups: normal control group(Group N),DN group(Group D),blank vector group(Group K,model rat was treated with 3×108PFU adenovirus vector via a penile vein injection at 8 week),Ang-1treatment group(Group A,model rat was treated with 3×108PFU Ad-Ang-1 via a penile vein injection at 8 week),L-mimosinetreatment group(Group L,model rat was treated with 50mg/kg L-mimosine via intraperitoneal injection every other day at 8week),and Ang-1 + L-mimosine treatment group(Group AL,model rat was treated with both Ad-Ang-1 and L-mimosine with their former method).At 12 and 16 weeks,their sample of blood,urinary,and kidney were collected.The blood glucose,serum creatinine,urea and urinary protein were observed.The renal pathological changes was observed by conventional HE and PAS staining.The levels of apoptosis-related protein(cleaved CASP3,CASP3,BAX,and BCL-2)were evaluated by western bloting(WB).The apoptotic state of renal inherent cells was observed by TUNEL.Results:1.The blood glucose and 24-hour urinary protein(24h UPRO): The levels of blood glucose and 24 h UPRO in five diabetic model groups were significantly higher than that of Group N(P<0.01),and the level of 24 h UPRO in Groups L and AL was significantly lower than that of Groups D and A(P<0.05).2.Serum creatinine and urea: The serum creatinine and urea levels in five diabetic model the increased creatinine was no difference,but the increased urea at 12 W was highgroups were upregulated at different degrees as compared with Group N,and their levels in three interventional groups were no difference(P>0.05).Compared with Group D,erin three interventional groups(P<0.01).3.Renal pathology: The glomerular size,mesangial matrix,and number of cells were increased with dilatation of partial tubular and Bowman's capsule,and infiltration of inflammatory cells in the five diabetic model groups,but their changes in three interventional groups were relatively reduced.4.Apoptosis-related protein in the renal tissue:(1)Compared with Group N,the cleaved CASPthree expression was significantly up-regulated,(P<0.01),and the CASP3 expression significantly down-regulated(P<0.01)in five diabetic model groups.The cleaved CASP3 expression was significantly lower,while the CASP3 expression was significantly higher in three interventional groups than Group D(P<0.01).No significant difference of cleaved CASP3 or CASP3 expressional levels were found between three interventional groups(P>0.05).(2)The BAX expression in five diabetic model groups was significantly up-regulated as compared with Group N(P<0.01).Its level in three interventional groups was significantly lower than that of Group D(P<0.01),and no significant difference was found between three interventional groups(P>0.05).(3)The BCL-2 expression in five diabetic model groups was significantly down-regulated as compared with Group N(P<0.05).Its level in three interventional groups was significantly higher than that of Group D(P<0.05),and no significant difference was found between three interventional groups(P>0.05).(4)The BAX/BCL-2 ratio in five diabetic model groups was significantly up-regulated as compared with Group N(P<0.01).Its ratio in three intervention groups was significantly lower than that of Group D(P<0.01),and no significant difference was found between three interventional groups(P>0.05).5.Cell apoptosis rate in the renal tissue: The apoptotic cells were mainly observed in renal tubular epithelial cells and mesangial cells.The cell apoptosis rate in five diabetic model groups was significantly up-regulated as compared with Group N(P<0.01).Its rate in three interventional groups was significantly lower than that of Group D(P<0.01),and no significant difference was found between three interventional groups(P>0.05).6.Cell apoptosis rate was positively correlated with the cleaved CASP3 and BAX expression and the BAX/BCL-2ratio(P<0.01),and its rate was negatively correlated with the CASP3 and BCL-2 expression(P<0.01).Conclusion:Ang-1 and L-mimosine can reduce apoptosis of renal inherent cells,which is associated with the improvementof apoptosis-related protein expression in diabetic renal tissue.This effect of alone or combined Ang-1 and L-mimosine in diabetic rats may be not significantly different. |
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